The proposed work investigates the metabolic effects of partial biliary obstruction in the rat. Though the summary changes of total biliary obstruction have received much study, there is little understanding of the early, sequential alterations in hepatic lipid metabolism, during elevated biliary pressures as might develop, for instance, in the setting of certain progressive human diseases. To study these early effects a rat model of partial biliary obstruction will be used, in which the effects of pressure on bile flows, bile cholesterol, phospholipid and bile salt concentration, hepatic cholesterol synthesis, hepatic lipids, and plasma lipids will be assessed.